Claude Code keeps a list of special file and folder names inside its own configuration directory (where it stores settings, sessions, logs and so on) that it treats differently from ordinary project files. That list has grown substantially, adding dozens of new reserved names covering things like usage data, caches, telemetry, task state, remote settings, and skill storage.
A related new function reads a per-skill claim file to determine skill ownership, capped at a size limit; if that file is too large, unreadable, or missing, it falls back to treating everything as claimed.
Reserving these names prevents Claude Code's own internal bookkeeping files from colliding with anything a user or project might otherwise place in that directory, and supports newer features (like skills, daemons, and remote settings) that need their own protected storage.